title: Age-associated alterations in γδ T-cells are present predominantly in individuals infected with Cytomegalovirus.
abstract: BACKGROUND
  Despite the common perception that latent Cytomegalovirus (CMV) infection is usually symptom-free, emerging epidemiological evidence suggests that it may in fact be associated with higher mortality over extended follow-up. Mechanisms responsible for this potentially important effect are unclear. CMV infection is known to have a large impact on the distribution of T cell phenotypes, especially the accumulation of late-stage differentiated CD8+, as well as Vδ2- γδ T-cells, which are the main subset of γδ T-cells involved in anti-CMV immunity. Its impact on γδ T-cells in the aging context is less well-defined.
  
  
  RESULTS
  Here, we investigated a group of healthy individuals aged between 21 and 89 years, in order to correlate the frequency and differentiation status of γδ T-cells with age. We found that these parameters were only marginally influenced by age, but were marked in people with a latent CMV infection. Thus, we observed a significant age-associated accumulation of late-differentiated T-cells within the Vδ2- population, but only in CMV-seropositive donors. There was also a strong trend towards reduced frequency of early-differentiated cells within the Vδ2- phenotype. Older people had significantly higher anti-CMV IgG titers, which in turn correlated significantly with a lower Vδ2+/Vδ2- ratio and a shift from early- to a late-differentiated Vδ2- T-cell phenotype.
  
  
  CONCLUSIONS
  Our findings demonstrate a strong influence of CMV on γδ T-cells during human ageing, similar to that observed for αβ T-cells. Differences between donors of different ages are more marked in CMV-infected individuals. The biological implications of this potent age-associated CMV-mediated immune-modulation require clarification.
authors.affiliation: Department of Internal Medicine II, Centre for Medical Research, University of Tübingen, Tübingen, Germany. evelyna.derhovanessian@klinikum.uni-tuebingen.de.
authors.forename: Kilian
authors.initials: K
authors.lastname: Wistuba-Hamprecht
authors.forename: Daniela
authors.initials: D
authors.lastname: Frasca
authors.forename: Bonnie
authors.initials: B
authors.lastname: Blomberg
authors.forename: Graham
authors.initials: G
authors.lastname: Pawelec
authors.forename: Evelyna
authors.initials: E
authors.lastname: Derhovanessian